• 제목/요약/키워드: Louisiana

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External mechanisms driving ecosystem changes in a coastal wetland, the Mississippi Delta, USA

  • Ryu, Junghyung;Liu, Kam-biu;McCloskey, Terrence A.;Yun, Sang-Leen
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2022년도 학술발표회
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    • pp.85-85
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    • 2022
  • The world's most extensive and active deltas, Louisiana's wetlands, are deteriorating rapidly due to multiple stressors such as the discharge of the Mississippi River, sea-level rise, and coastal retreat, the substantial but spatially and temporally variable impacts. However, the ecological and anthropogenic histories, the mode of environmental changes on a multi-millennial timescale have not been thoroughly documented. This study, a palynology-based multiproxy analysis, investigates hydrological, geological, geochemical, and anthropogenic impacts on southern Louisiana wetlands and a variety of external forcing agents influencing ecological succession. Sediment cores extracted from a small pond on a mangrove-dominate island near Port Fourchon, Louisiana, USA yielded a 4,000-year record. The site has been transformed from freshwater to saline water environments, to a mangrove dominant island over the late Holocene. The multivariate principal component analysis identified the relative strength of external drivers responsible for each ecological shift. The Mississippi River delta cycle (lobe switching) was the dominant driver of ecosystem changes during the late Holocene, while relative sea-level rise, tropical cyclones, climate, and anthropogenic effects have been the main drivers late in the site's history.

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루이지아나 현대미술관에 나타난 공간경험 및 설계특성에 관한 연구 (A Study on the Spatial Experience and Design Characteristics in Louisiana Museum of Modern Art)

  • 김종진
    • 한국실내디자인학회논문집
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    • 제20권6호
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    • pp.44-52
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    • 2011
  • Louisiana Museum of Modern Art near Copenhagen is the most visited art museum in Denmark. It was originally founded by the director of the time, Knud W. Jensen and designed by two Danish architects, Vilhelm Wohlert and J${\o}$rgen Bo. The first part of the museum was built and opened to the public in 1958. The first part consisted of just a few exhibition spaces and glass corridors. But museum has been expanded step by step into a large park-like museum throughout 40 years of time. Louisiana museum has a unique environment in which art, architecture and nature are inter-related together. There was a very clear background for this museum atmosphere that was created by Knud W. Jensen from the very beginning. He wanted to make 'a sculptural park' or 'a low pavilion in the park'. The concept of 'park' was the key element. The architects, especially Vilhelm Wohlert who studied at the western area of the United States and influenced by the bay area architecture as well as the oriental wooden structure, interacted with the director's idea fully and made an invisible architecture in which 'Experience of Space' is the most important aspect. This thesis aims to analyze several crucial spaces of the museum and to find a hidden design characteristics. Chapter 2&3 explains general backgrounds and main design philosophy. Chapter 4 studies each parts' spatial experience and design methods with 3-dimensional diagrams. Chapter 5 tries to make an overall design characteristics that underlines the whole museum environment. The significance of Louisiana museum is not only in the fact that it is the most visited, but also in the fact that the role of architecture is to make a better environment where human and art are harmonized together within nature. The utopian idea of the founder started in doubt almost 50 years ago has been already successful in this small but vibrant park.

Moisture Concentration Variation of Silages Produced on Commercial Farms in the South-Central USA

  • Han, K.J.;Pitman, W.D.;Chapple, A.
    • Asian-Australasian Journal of Animal Sciences
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    • 제27권10호
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    • pp.1436-1442
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    • 2014
  • Preservation of forage crops as silage offers opportunity to avoid the high risk of rain-damaged hay in the humid south-central USA. Recent developments with baled silage or baleage make silage a less expensive option than typical chopped silage. Silage has been important in the region primarily for dairy production, but baleage has become an option for the more extensive beef cattle industry in the region. Silage samples submitted to the Louisiana State University Agricultural Center Forage Quality Lab from 2006 through 2013 were assessed for dry matter (DM) and forage nutritive characteristics of chopped silage and baleage of the different forage types from commercial farms primarily in Louisiana and Mississippi. Of the 1,308 silage samples submitted, 1,065 were annual ryegrass (AR) with small grains (SG), the warm-season annual (WA) grasses, sorghums and pearl millet, and the warm-season perennial (WP) grasses, bermudagrass and bahiagrass, providing the remaining samples. Concentration of DM was used to indicate an effective ensiling opportunity, and AR silage was more frequently within the target DM range than was the WA forage group. The AR samples also indicated a high-quality forage with average crude protein (CP) of 130 g/kg and total digestible nutrient (TDN) near 600 g/kg. The cooler winter weather at harvest apparently complicated harvest of SG silage with chopped SG silage lower in both CP and TDN (104 and 553 g/kg, respectively) than either AR silage or baleage of SG (137 and 624 g/kg for CP and TDN, respectively). The hot, humid summer weather along with large stems and large forage quantities of the WA grasses and the inherently higher fiber concentration of WP grasses at harvest stage indicate that preservation of these forage types as silage will be challenging, although successful commercial silage samples of each forage type and preservation approach were included among samples of silages produced in the region.

Crosstalk between integrin and receptor tyrosine kinase signaling in breast carcinoma progression

  • Soung, Young-Hwa;Clifford, John L.;Chung, Jun
    • BMB Reports
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    • 제43권5호
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    • pp.311-318
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    • 2010
  • This review explored the mechanism of breast carcinoma progression by focusing on integrins and receptor tyrosine kinases (or growth factor receptors). While the primary role of integrins was previously thought to be solely as mediators of adhesive interactions between cells and extracellular matrices, it is now believed that integrins also regulate signaling pathways that control cancer cell growth, survival, and invasion. A large body of evidence suggests that the cooperation between integrin and receptor tyrosine kinase signaling regulates certain signaling functions that are important for cancer progression. Recent developments on the crosstalk between integrins and receptor tyrosine kinases, and its implication in mammary tumor progression, are discussed.

A coupled wind-vehicle-bridge system and its applications: a review

  • Cai, C.S.;Hu, Jiexuan;Chen, Suren;Han, Yan;Zhang, Wei;Kong, Xuan
    • Wind and Structures
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    • 제20권2호
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    • pp.117-142
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    • 2015
  • The performance of bridges under strong wind and traffic is of great importance to set the traveling speed limit or to make operational decisions for severe weather, such as controlling traffic or even closing the bridge. Meanwhile, the vehicle's safety is highly concerned when it is running on bridges or highways under strong wind. During the past two decades, researchers have made significant contributions to the simulation of the wind-vehicle-bridge system and their interactive effects. This paper aims to provide a comprehensive review of the overall performance of the bridge and traffic system under strong wind, including bridge structures and vehicles, and the associated mitigation efforts.

Virus-like Particles and Cellular Changes in Plants Infected with Sweetpotato Viruses

  • Sim, Jeong-Gu;Valverde, Rodrigo;Clark, Christopher;Chun, Se-Chul
    • The Plant Pathology Journal
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    • 제24권1호
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    • pp.36-45
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    • 2008
  • Studies with the transmission electron microscope were used to detect and attempt to identify viruses infecting sweetpotato (Ipomoea batatas) and other Ipomoea species. Flexuous-rods, short curved-rods, and spherical virus-like particles were observed in cells of symptomatic plants. Also, various cytopathic changes such as crystals, vesicles, fibril structures, and cylindrical inclusions were observed. The present study showed that some of these cytopathic changes were associated with some viral groups, which might be helpful in diagnosis.

The Swelling Response of Loblolly Pine (Pinus Taeda) Juvenile Wood to Water Submersion

  • Via, Brain K.;Hartley, Ian D.;Shupe, Todd F.;Lee, Sang Yeob;Lee, Byung G.
    • Journal of the Korean Wood Science and Technology
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    • 제33권2호통권130호
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    • pp.17-23
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    • 2005
  • Juvenile and transitional-juvenile wood samples from loblolly pine (Pinus taeda) were immersed in water to investigate longitudinal and tangential swelling properties. Increment cores from twenty-six loblolly pine trees were sampled at breast height (1.37 m). Earlywood rings 5 and 9 were separated from the core, extracted, oven-dried and immersed in water at room temperature. The variance in longitudinal swell was significant for ring 5 compared to ring 9 (p = 0.001). It was found that tangential swell might predict longitudinal swelling of juvenile wood at ring 9 but not at ring 5. Poor correlation in ring 5 suggests that swelling response in younger juvenile wood may differ. The swell response at ring 5 did not follow the shrinkage models discussed in the literature while ring 9 adhered to the expected curve.

INVESTIGATION OF THE MEANDER PLANFORM DEVELOPMENT IN A LABORATORY CHANNEL

  • Yilmaz, L.;Singh, Vijay P.;Mishra, S.K.;Adrian, D.D.;Sansalone, J.J.
    • Water Engineering Research
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    • 제3권3호
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    • pp.177-193
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    • 2002
  • Experiments were conducted in an initially straight laboratory alluvial channel to investigate channel meandering characteristics. The experimental observations revealed an empirical relation between three types of tortuosity ratios used for describing meandering characteristics. Furthermore, the Strauhal number was found to be higher for bed material with greater resistance to erosion than with lower resistance to erosion. The meandering characteristics were also investigated using the concept of buckling employed in solid mechanics and the concept of siphoning of fluid mechanics. The buckling of flow, attributable to the flow nonuniformity across the channel cross-section, was found to follow the same pattern as did meandering observed experimentally. The processes of expansion of meanders and cut-off can be explained using the concept of siphoning. The results of expanding meander planforms observed in four experimental tests supported the viability of these concepts.

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Deuterium NMR Studies of $({\mu}_3-C^2H)[Co(CO)_3]_3$

  • Woo, Ae-Ja;Maria I. Altbach;Leslie G. Butler
    • 한국자기공명학회논문지
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    • 제1권2호
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    • pp.95-102
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    • 1997
  • Deuterium quadrupole coupling constant (e2qzzQ/h) of ($\mu$3-C2H)[Co(CO)3]3 was determined by using solid-state deuterium MAS NMR spectroscopy. The small quadrupole coupling constant of bridging methyne unit relative to sp-acethylene in propyne is discussed in terms of the C-H bond length and the negative charge on the carbon.

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A COMPARATIVE EVALUATION OF THE ESTIMATORS OF THE 2-PARAMETER GENERALIZED PARETO DISTRIBUTION

  • Singh, V.P.;Ahmad, M.;Sherif, M.M.
    • Water Engineering Research
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    • 제4권3호
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    • pp.155-173
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    • 2003
  • Parameters and quantiles of the 2-parameter generalized Pareto distribution were estimated using the methods of regular moments, modified moments, probability weighted moments, linear moments, maximum likelihood, and entropy for Monte Carlo-generated samples. The performance of these seven estimators was statistically compared, with the objective of identifying the most robust estimator. It was found that in general the methods of probability-weighted moments and L-moments performed better than the methods of maximum likelihood estimation, moments and entropy, especially for smaller values of the coefficient of variation and probability of exceedance.

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